'You ain't too plain, sugarcube...'

So here, Dinky is crushed that Pipsqueak broke up with her and began dating Sweetie Belle, who by this time, has grown up looking as beautiful as her sister. She wonders if it's because she had gotten too plain for Pip's tastes, but Apple Bloom tries to convince her otherwise.

...so why has Pip broken up with Dinky and chosen Sweetie Belle? Well, Sweetie Belle was my second choice for a fillyfriend for him, and I was like 'I want to try a plot that involves Pip briefly falling for Sweetie Belle after they meet at her birthday party.' ...Luckily, it doesn't turn into a pony version of School Days.